1 files changed, 406 insertions, 0 deletions

diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c
new file mode 100644
index 000000000000..5429041c7eaf
--- /dev/null
+++ b/fs/exfat/balloc.c
@@ -0,0 +1,406 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include <linux/bitmap.h>
+#include <linux/buffer_head.h>
+#include <linux/backing-dev.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+#if BITS_PER_LONG == 32
+#define __le_long __le32
+#define lel_to_cpu(A) le32_to_cpu(A)
+#define cpu_to_lel(A) cpu_to_le32(A)
+#elif BITS_PER_LONG == 64
+#define __le_long __le64
+#define lel_to_cpu(A) le64_to_cpu(A)
+#define cpu_to_lel(A) cpu_to_le64(A)
+#else
+#error "BITS_PER_LONG not 32 or 64"
+#endif
+
+/*
+ *  Allocation Bitmap Management Functions
+ */
+static bool exfat_test_bitmap_range(struct super_block *sb, unsigned int clu,
+		unsigned int count)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	unsigned int start = clu;
+	unsigned int end = clu + count;
+	unsigned int ent_idx, i, b;
+	unsigned int bit_offset, bits_to_check;
+	__le_long *bitmap_le;
+	unsigned long mask, word;
+
+	if (!is_valid_cluster(sbi, start) || !is_valid_cluster(sbi, end - 1))
+		return false;
+
+	while (start < end) {
+		ent_idx = CLUSTER_TO_BITMAP_ENT(start);
+		i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
+		b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
+
+		bitmap_le = (__le_long *)sbi->vol_amap[i]->b_data;
+
+		/* Calculate how many bits we can check in the current word */
+		bit_offset = b % BITS_PER_LONG;
+		bits_to_check = min(end - start,
+				    (unsigned int)(BITS_PER_LONG - bit_offset));
+
+		/* Create a bitmask for the range of bits to check */
+		if (bits_to_check >= BITS_PER_LONG)
+			mask = ~0UL;
+		else
+			mask = ((1UL << bits_to_check) - 1) << bit_offset;
+		word = lel_to_cpu(bitmap_le[b / BITS_PER_LONG]);
+
+		/* Check if all bits in the mask are set */
+		if ((word & mask) != mask)
+			return false;
+
+		start += bits_to_check;
+	}
+
+	return true;
+}
+
+static int exfat_allocate_bitmap(struct super_block *sb,
+		struct exfat_dentry *ep)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct blk_plug plug;
+	long long map_size;
+	unsigned int i, j, need_map_size;
+	sector_t sector;
+	unsigned int max_ra_count;
+
+	sbi->map_clu = le32_to_cpu(ep->dentry.bitmap.start_clu);
+	map_size = le64_to_cpu(ep->dentry.bitmap.size);
+	need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE)
+		+ 1;
+	if (need_map_size != map_size) {
+		exfat_err(sb, "bogus allocation bitmap size(need : %u, cur : %lld)",
+			  need_map_size, map_size);
+		/*
+		 * Only allowed when bogus allocation
+		 * bitmap size is large
+		 */
+		if (need_map_size > map_size)
+			return -EIO;
+	}
+	sbi->map_sectors = ((need_map_size - 1) >>
+			(sb->s_blocksize_bits)) + 1;
+	sbi->vol_amap = kvmalloc_array(sbi->map_sectors,
+				sizeof(struct buffer_head *), GFP_KERNEL);
+	if (!sbi->vol_amap)
+		return -ENOMEM;
+
+	sector = exfat_cluster_to_sector(sbi, sbi->map_clu);
+	max_ra_count = min(sb->s_bdi->ra_pages, sb->s_bdi->io_pages) <<
+		(PAGE_SHIFT - sb->s_blocksize_bits);
+	for (i = 0; i < sbi->map_sectors; i++) {
+		/* Trigger the next readahead in advance. */
+		if (max_ra_count && 0 == (i % max_ra_count)) {
+			blk_start_plug(&plug);
+			for (j = i; j < min(max_ra_count, sbi->map_sectors - i) + i; j++)
+				sb_breadahead(sb, sector + j);
+			blk_finish_plug(&plug);
+		}
+
+		sbi->vol_amap[i] = sb_bread(sb, sector + i);
+		if (!sbi->vol_amap[i])
+			goto err_out;
+	}
+
+	if (exfat_test_bitmap_range(sb, sbi->map_clu,
+		EXFAT_B_TO_CLU_ROUND_UP(map_size, sbi)) == false)
+		goto err_out;
+
+	return 0;
+
+err_out:
+	j = 0;
+	/* release all buffers and free vol_amap */
+	while (j < i)
+		brelse(sbi->vol_amap[j++]);
+
+	kvfree(sbi->vol_amap);
+	sbi->vol_amap = NULL;
+	return -EIO;
+}
+
+int exfat_load_bitmap(struct super_block *sb)
+{
+	unsigned int i, type;
+	struct exfat_chain clu;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
+	while (clu.dir != EXFAT_EOF_CLUSTER) {
+		for (i = 0; i < sbi->dentries_per_clu; i++) {
+			struct exfat_dentry *ep;
+			struct buffer_head *bh;
+
+			ep = exfat_get_dentry(sb, &clu, i, &bh);
+			if (!ep)
+				return -EIO;
+
+			type = exfat_get_entry_type(ep);
+			if (type == TYPE_BITMAP &&
+			    ep->dentry.bitmap.flags == 0x0) {
+				int err;
+
+				err = exfat_allocate_bitmap(sb, ep);
+				brelse(bh);
+				return err;
+			}
+			brelse(bh);
+
+			if (type == TYPE_UNUSED)
+				return -EINVAL;
+		}
+
+		if (exfat_get_next_cluster(sb, &clu.dir))
+			return -EIO;
+	}
+
+	return -EINVAL;
+}
+
+void exfat_free_bitmap(struct exfat_sb_info *sbi)
+{
+	int i;
+
+	for (i = 0; i < sbi->map_sectors; i++)
+		__brelse(sbi->vol_amap[i]);
+
+	kvfree(sbi->vol_amap);
+}
+
+int exfat_set_bitmap(struct super_block *sb, unsigned int clu, bool sync)
+{
+	int i, b;
+	unsigned int ent_idx;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	if (!is_valid_cluster(sbi, clu))
+		return -EINVAL;
+
+	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
+	i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
+	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
+
+	set_bit_le(b, sbi->vol_amap[i]->b_data);
+	exfat_update_bh(sbi->vol_amap[i], sync);
+	return 0;
+}
+
+int exfat_clear_bitmap(struct super_block *sb, unsigned int clu, bool sync)
+{
+	int i, b;
+	unsigned int ent_idx;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	if (!is_valid_cluster(sbi, clu))
+		return -EIO;
+
+	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
+	i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
+	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
+
+	if (!test_bit_le(b, sbi->vol_amap[i]->b_data))
+		return -EIO;
+
+	clear_bit_le(b, sbi->vol_amap[i]->b_data);
+
+	exfat_update_bh(sbi->vol_amap[i], sync);
+
+	return 0;
+}
+
+bool exfat_test_bitmap(struct super_block *sb, unsigned int clu)
+{
+	int i, b;
+	unsigned int ent_idx;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	if (!sbi->vol_amap)
+		return true;
+
+	if (!is_valid_cluster(sbi, clu))
+		return false;
+
+	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
+	i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
+	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
+
+	if (!test_bit_le(b, sbi->vol_amap[i]->b_data))
+		return false;
+
+	return true;
+}
+
+/*
+ * If the value of "clu" is 0, it means cluster 2 which is the first cluster of
+ * the cluster heap.
+ */
+unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu)
+{
+	unsigned int i, map_i, map_b, ent_idx;
+	unsigned int clu_base, clu_free;
+	unsigned long clu_bits, clu_mask;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	__le_long bitval;
+
+	WARN_ON(clu < EXFAT_FIRST_CLUSTER);
+	ent_idx = ALIGN_DOWN(CLUSTER_TO_BITMAP_ENT(clu), BITS_PER_LONG);
+	clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx);
+	clu_mask = IGNORED_BITS_REMAINED(clu, clu_base);
+
+	map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
+	map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx);
+
+	for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters;
+	     i += BITS_PER_LONG) {
+		bitval = *(__le_long *)(sbi->vol_amap[map_i]->b_data + map_b);
+		if (clu_mask > 0) {
+			bitval |= cpu_to_lel(clu_mask);
+			clu_mask = 0;
+		}
+		if (lel_to_cpu(bitval) != ULONG_MAX) {
+			clu_bits = lel_to_cpu(bitval);
+			clu_free = clu_base + ffz(clu_bits);
+			if (clu_free < sbi->num_clusters)
+				return clu_free;
+		}
+		clu_base += BITS_PER_LONG;
+		map_b += sizeof(long);
+
+		if (map_b >= sb->s_blocksize ||
+		    clu_base >= sbi->num_clusters) {
+			if (++map_i >= sbi->map_sectors) {
+				clu_base = EXFAT_FIRST_CLUSTER;
+				map_i = 0;
+			}
+			map_b = 0;
+		}
+	}
+
+	return EXFAT_EOF_CLUSTER;
+}
+
+int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	unsigned int count = 0;
+	unsigned int i, map_i = 0, map_b = 0;
+	unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi);
+	unsigned int last_mask = total_clus & (BITS_PER_LONG - 1);
+	unsigned long *bitmap, clu_bits;
+
+	total_clus &= ~last_mask;
+	for (i = 0; i < total_clus; i += BITS_PER_LONG) {
+		bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
+		count += hweight_long(*bitmap);
+		map_b += sizeof(long);
+		if (map_b >= (unsigned int)sb->s_blocksize) {
+			map_i++;
+			map_b = 0;
+		}
+	}
+
+	if (last_mask) {
+		bitmap = (void *)(sbi->vol_amap[map_i]->b_data + map_b);
+		clu_bits = lel_to_cpu(*(__le_long *)bitmap);
+		count += hweight_long(clu_bits & BITMAP_LAST_WORD_MASK(last_mask));
+	}
+
+	*ret_count = count;
+	return 0;
+}
+
+int exfat_trim_fs(struct inode *inode, struct fstrim_range *range)
+{
+	unsigned int trim_begin, trim_end, count, next_free_clu;
+	u64 clu_start, clu_end, trim_minlen, trimmed_total = 0;
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	int err = 0;
+
+	clu_start = max_t(u64, range->start >> sbi->cluster_size_bits,
+				EXFAT_FIRST_CLUSTER);
+	clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1;
+	trim_minlen = range->minlen >> sbi->cluster_size_bits;
+
+	if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size)
+		return -EINVAL;
+
+	if (clu_end >= sbi->num_clusters)
+		clu_end = sbi->num_clusters - 1;
+
+	mutex_lock(&sbi->bitmap_lock);
+
+	trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start);
+	if (trim_begin == EXFAT_EOF_CLUSTER)
+		goto unlock;
+
+	next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1);
+	if (next_free_clu == EXFAT_EOF_CLUSTER)
+		goto unlock;
+
+	do {
+		if (next_free_clu == trim_end + 1) {
+			/* extend trim range for continuous free cluster */
+			trim_end++;
+		} else {
+			/* trim current range if it's larger than trim_minlen */
+			count = trim_end - trim_begin + 1;
+			if (count >= trim_minlen) {
+				err = sb_issue_discard(sb,
+					exfat_cluster_to_sector(sbi, trim_begin),
+					count * sbi->sect_per_clus, GFP_NOFS, 0);
+				if (err)
+					goto unlock;
+
+				trimmed_total += count;
+			}
+
+			/* set next start point of the free hole */
+			trim_begin = trim_end = next_free_clu;
+		}
+
+		if (next_free_clu >= clu_end)
+			break;
+
+		if (fatal_signal_pending(current)) {
+			err = -ERESTARTSYS;
+			goto unlock;
+		}
+
+		next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1);
+	} while (next_free_clu != EXFAT_EOF_CLUSTER &&
+			next_free_clu > trim_end);
+
+	/* try to trim remainder */
+	count = trim_end - trim_begin + 1;
+	if (count >= trim_minlen) {
+		err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin),
+			count * sbi->sect_per_clus, GFP_NOFS, 0);
+		if (err)
+			goto unlock;
+
+		trimmed_total += count;
+	}
+
+unlock:
+	mutex_unlock(&sbi->bitmap_lock);
+	range->len = trimmed_total << sbi->cluster_size_bits;
+
+	return err;
+}